1. Field of Invention
The present invention relates to a shuttlecock and a manufacturing method thereof, and more particularly to a shuttlecock comprising a connecting apparatus for coupling a shuttlecock head with a set of feather units, and its manufacturing method.
2. Description of Related Arts
Badminton is a beneficial racquet game for exercising, and since there is no intensive physical contact, it is suitable for people of all ages. However, the sports sites, the supporting facilities, and the manufacturing process of the shuttlecocks still restrict the development of the game, and thus result in a relatively low penetration rate of the game.
In addition, when manufacturing a shuttlecock in a conventional process, sixteen natural feathers are subject to a simple preparing process so that they substantially have a same length and a same shape, then these natural feathers are inserted into a shuttlecock head. In order to ensure the flying stability of the shuttlecock, all of the feathers of the shuttlecock are required to have a good consistence. As we all know, a feather comprises two parts which are the shaft portion and the feather portion. The so-called consistence of the feather requires the length, the degree of curvature, the degree of arch, the toughness, and the thickness of the shaft portions to be consistent, as well as requiring the shape, size, and color of the feather portions to be consistent. Through tailoring and selecting process, it is available to make the shape, size, and color of the feather portions be consistent. However, it is not likely to make the shaft portions of the feathers of the shuttlecock be consistent. That is because the feathers are natural feathers, so even the feathers are obtained from a same goose or duck, it is not likely to make the gradually decreasing rate of the length, the degree of curvature, the degree of arch, the toughness, and the thickness of all shaft portions be consistent, so that it is not possible to obtain consistent shaft portions of the feathers. Therefore, since the material for manufacturing a shuttlecock is not able to provide feathers with shaft portions of good consistence, there is an inevitable disadvantage for the conventional shuttlecock that that the flying stability is not good.
Because the quality of the goose feathers are better than the quality of the duck feathers, particularly, the shaft portions of goose feathers, which have relatively strong toughness, are not easy to fracture, while the shaft portions of duck feathers, which have relatively weak toughness, are easy to fracture, so that the durability of the shuttlecocks made of goose feathers is better than the durability of the shuttlecocks made of duck feathers. Furthermore, the period for raising ducks from eggs to be mature for harvesting feathers is about ninety days, but the period for a goose is about one hundred and twenty days, so that the costs for manufacturing shuttlecocks made of goose feathers and are of good quality are relatively high.
Additionally, in order to ensure that the shuttlecocks are able to fly in a spinning manner, all of the feathers are inserted into the shuttlecock head side by side in a staggered manner so that all of the feathers are constructed to be vortex-shaped. In other words, each of the feathers is arranged to have an eccentric angle, and each two adjacent feather portions of the feathers define a gap therebetween. In order to ensure that the shuttlecock is able to fly stably, all of the gaps are preferred to have a same size and distance. In a conventional shuttlecock, since the shaft portions of the natural feathers are directly inserted in the shuttle head, the insertion holes in the shuttlecock head are not easy to be constructed to have a shape matching the shape of the shaft portions of the feathers, the eccentric angles of the insertion holes are even harder to be arranged correctly, so that the eccentric angle of each of the feathers is hard to control, and thus the eccentric angles varied to a large extent, and result in a weak flying stability of the shuttlecocks.
Furthermore, as mentioned above, since it is impossible to keep the toughness, thickness, and curvature of the shaft portions of all feathers of a shuttlecock to be consistent, when the shuttlecock is applied with a strong impact force via a shuttlecock racket, the force is not distributed consistently along each shaft portion, so that not only the flying stability of the shuttlecock is influenced, but also the shaft portions are easy to fracture. Once the shaft portions are damaged, the whole shuttlecock cannot be used.
In addition, a quality test should be carried out when the shuttlecocks finish the manufacturing process. The test introduces a testing device to violently strike the shuttlecocks, and the impact force is larger than the force of a common user when striking the shuttlecocks, so that because the shaft portions are not able to be consistent, many shuttlecocks fracture after striking by the testing device, for the shaft portions of the feathers are not evenly applied with the impact force. Therefore, many shuttlecocks are abandoned before selling into the market for using. Thus, not only the production rate of the shuttlecocks is relatively low, but also it results in a large waste, and the manufacturing costs of the shuttlecocks are relatively high.
In a word, the output of the feathers is limited, and the natural feathers are not replaceable, so that the output of the conventional shuttlecocks is limited. And because the natural feathers have a bad consistence, especially it is hard to meet the requirement of the consistence of the thickness, curvature, and toughness of the shaft portions of the all feathers of the shuttlecock, the quality of the most conventional shuttlecocks is not good, and thus the price of the shuttlecocks of good quality is relatively high, so that the penetrate rate of badminton is influenced.
In order for better understanding the influence of the conventional shuttlecocks on badminton, the structure of the conventional shuttlecocks and manufacturing method thereof are illustrated in the following description. Referring to FIG. 1 of the drawings, a conventional shuttlecock is illustrated. The conventional shuttlecock comprises a shuttlecock head 10′, a set of feather 30′ inserted into the shuttlecock head 10′, and a connecting string 40′ for connecting and fixing the set of feather 30′. The number of the feathers 30′ is sixteen, the length of the each feather 30′ is 62-77 mm. Each feather 30′ has a shaft portion 31′ and a feather portion 32′ which has a length about 35-40% of the total length of the entire feather. The lower portion of each feather 30′ is inserted into the outer circumference of the shuttlecock head 10′, and is further fixed and retained in position by glues, the upper portion of each feather 30′ is connected and fixed by the connecting string 40′, so that all of the feathers 30′ are connected to form a one-piece structure, so as to ensure that the feathers 30′ can evenly withstand the impact force of the shuttlecock racket, so that the flying stability of the shuttlecock is improved. However, once one of the shaft portions 31′ fracture, since it is replaceable, the whole shuttlecock cannot be used.
Referring to FIG. 2 of the drawings, the connecting string 40′ connects the shaft portions 31′ of the sixteen feathers 30′ in series manually by human hands in a staggered and twisted manner, and then the binding positions between the connecting string 40′ and each shaft portion 31′ is provided with glues for enhancing the stability of the connection in series therebetween. As is well known in the art, there is a problem that it is difficult to ensure a same angle between each two adjacent shaft portions 31′ when connecting the shaft portions 31′ of the feathers 30′ in series manually by human hands in a staggered and twisted manner. Therefore, not only the flying stability of the shuttlecock is influenced, but also some of the shaft portions 31′ will fracture for the shaft portions 31′ are not able to evenly distribute impact force when the shuttlecock is under a strike.
The method for manufacturing the conventional shuttlecock comprises the following steps.
(1) Select and tailor sixteen feathers 30′ which fit predetermined requirements, each feather 30′ has a length of 62-77 mm and includes a shaft portion 31′ and a feather portion 32′, wherein a length of the feather portion 32′ is 35-40% of the length of the entire feather, all of the feathers of the shuttlecock have a same length and each shaft portion 31′ has a same length. Most importantly, the shaft portions 31′ of the sixteen feathers of the shuttlecock should be consistent. Not only each shaft portion should have a same length, the toughness, curvature, and the thickness of each shaft portion should be substantially the same.
(2) Insert the shaft portions 31′ of the sixteen feathers 30′ into insertion grooves 11′ of the shuttlecock 10′ one by one.
(3) Connect the shaft portions 31′ of the sixteen feathers 30′ in series manually by human hands in a staggered and twisted manner by the connecting string 40′. Generally, this step will be repeated twice. In other words, two connecting strings 40′ are required to connect the shaft portions 31′ on different sites.
(4) Apply glues to the binding positions between the shaft portions 31′ and the shuttlecock head 10′, and the binding positions between the shaft portions 31′ and the connecting string 40′, so that the shaft portions 31′ is engaged with the shuttlecock head 10′ and the connecting string 40′ more stably, so that the feathers 30′, the shuttlecock head 10′, and the connecting string 40′ form an integral structure.
The above mentioned manufacturing method of the conventional shuttlecocks is mainly carried out by manual operations, so that there are several disadvantages. First of all, in the above step (1) for selecting and tailoring sixteen feathers 30′ which fit predetermined requirements, the main object of this step is to ensure that the shaft portions of the sixteen feathers of the shuttlecock have a good consistence. In other words, the toughness, curvature, and thickness of the shaft portions of the sixteen feathers should be the same, but the whole selecting process is competed based on the experience and sensibility of the worker, so that it is difficult to ensure that the shaft portions of the sixteen feathers of the shuttlecock have a good consistence, and thus the quality of the shuttlecock cannot be guaranteed. Secondly, in the above step (3) for connecting the shaft portions 31′ in series via the connecting string 40′, the angle between adjacent two shaft portions is hard to control, and the angle between each shaft portion 31′ and the shuttlecock head 10′ is also hard to control. In other words, the taper rate of the shuttlecock is hard to control. Thirdly, in the step (4), the amount of the glues cannot be controlled, usually resulting in an overweight of the shuttlecocks, so that the shuttlecocks cannot meet the standard requirements of the badminton matches. Fourthly, in the step (4), although the glues applied on the binding positions between the shaft portions 31′ and the shuttlecock 10′, and the binding positions between the shaft portions 31′ and the connecting string 40′ is beneficial for enhancing the engagement therebetween. However, because of the introduction of the glues, the part of the shaft portion applied with glues have a stiffness larger than the rest part of the shaft portion without glues, particularly the binding positions between the shaft portion and the connecting string may result in a relatively large stiffness, so that when the shuttlecock is under a strike by a shuttlecock racket, the shaft portions may fracture from the binding positions at the connecting string 40′. However, once one of the shaft portions fractures, the whole shuttlecock cannot be used. Fifthly, in order to keep the angle between two adjacent feathers to be the same, after using the connecting string 40′ to connect the shaft portions 31′ in series, not only the binding positions between the connecting string 40′ and each shaft portion 31′ are applied with glues, but also the whole connecting string 40′ is applied with glues, so that the connecting string 40′ is solidified to provide a support for the shaft portions 31′, so as to prevent the angle between the two adjacent shaft portions 31′ to vary during the flying of the shuttlecock to influence the flying stability of the shuttlecock. However, the amount of the glues is hard to control, when excess amount of the glues is applied, the resulting shuttlecock may be overweight, when the amount of the glues is not enough, the solidifying performance of the connecting string 40′ is not good. In addition, evenly applying the glues is also a problem for the operations are carried out based on the experience of the workers, so that the quality of the shuttlecocks may vary depending on the experience of the workers.
In a word, the efficiency of conventional method for manufacturing a shuttlecock is relatively low, and the requirement for the experience of the workers is relatively high, so that the manufacturing process cannot be standardized, and thus the quality of the conventional shuttlecocks is far from satisfied. Once the shaft portions fracture, the whole shuttlecock cannot be repaired, so that it results in a large waste.